Ainul Haezah Noruzman

Characteristics of treated effluents and their potential applications for producing concrete

Conservation and preservation of freshwater is increasingly becoming important as the global population grows. Presently, enormous volumes of freshwater are used to mix concrete. This paper reports experimental findings regarding the feasibility of using treated effluents as alternatives to freshwater in mixing concrete. Samples were obtained from three effluent sources: heavy industry, a palm-oil mill and domestic sewage. The effluents were discharge into public drain without danger to human health and natural environment. Chemical compositions and physical properties of the treated effluents were investigated. Fifteen compositional properties of each effluent were correlated with the requirements set out by the relevant standards. Concrete mixes were prepared using the effluents and freshwater to establish a base for control performance. The concrete samples were evaluated with regard to setting time, workability, compressive strength and permeability. The results show that except for some slight excesses in total solids and pH, the properties of the effluents satisfy the recommended disposal requirements. Two concrete samples performed well for all of the properties investigated. In fact, one sample was comparatively better in compressive strength than the normal concrete; a 9.4% increase was observed at the end of the curing period. Indeed, in addition to environmental conservation, the use of treated effluents as alternatives to freshwater for mixing concrete could save a large amount of freshwater, especially in arid zones.

Impact of Blending on Strength Distribution of Ambient Cured Metakaolin and Palm Oil Fuel Ash Based Geopolymer Mortar

This paper investigates the influence of blending of metakaolin with silica rich palm oil fuel ash (POFA) on the strength distribution of geopolymer mortar. The broadness of strength distribution of quasi-brittle to brittle materials depends strongly on the existence of flaws such as voids, microcracks, and impurities in the material. Blending of materials containing alumina and silica with the objective of improving the performance of geopolymer makes comprehensive characterization necessary. The Weibull distribution is used to study the strength distribution and the reliability of geopolymer mortar specimens prepared from 100% metakaolin, 50% and 70% palm and cured under ambient condition. Mortar prisms and cubes were used to test the materials in flexure and compression, respectively, at 28 days and the results were analyzed using Weibull distribution. In flexure, Weibull modulus increased with POFA replacement, indicating reduced broadness of strength distribution from an increased homogeneity of the material. Modulus, however, decreased with increase in replacement of POFA in the specimens tested under compression. It is concluded that Weibull distribution is suitable for analyses of the blended geopolymer system. While porous microstructure is mainly responsible for flexural failure, heterogeneity of reaction relics is responsible for the compression failure.

Characterization of some Key Industrial Waste Products for Sustainable Concrete Production

The use of environmentally friendly or green concrete to enable worldwide infrastructural development without increase in carbon dioxide (CO2) emission is at the focal point of the global issues concerning sustainability. Aside from the concerted efforts by the key players in the construction industry to successfully replace in part or in whole, the conventional Portland cement with green or eco-friendly cementitious materials, the challenges of ensuring that the so called green or eco-friendly concrete performs up to the required expectation has been the focus of many researches. This study therefore, provides an overview of the various processing techniques for the industrial waste materials as well as the determination of the physical and chemical characteristics of the powders prepared from the respective waste materials. The materials were characterized using BET surface area analysis, X-ray diffraction (XRD), Chemical analysis by X-ray fluorescence (XRF), 45-μm wet sieving, 75-μm and 150-μm dry sieving, Specific gravity using density bottle and reactivity index (RI). The results show that FA and PBC are very similar in terms of their physical and chemical characteristic in comparism with POFA. Notwithstanding, all the materials satisfy the basic requirements of the relevant ASTM specifications and also falls within the limit specified by ASTM C 618 for class F fly ash.

Early Strength Characteristics of Palm Oil Fuel Ash and Metakaolin Blended Geopolymer Mortar

In this paper, the early strength behavior of Metakaolin and Palm Oil Fuel Ash (POFA) based geopolymer mortar was investigated for the purpose of exploring the utilization of POFA which is a waste material generated from production of palm oil. Geopolymer mortar was prepared by activating metakaolin combined with POFA at 0%, 30%, 40%, 50%, 60%, 70% and 80% replacement levels in NaOH and Na2SiO3 medium. The mortar specimens were tested for compressive strength at 3 and 7days. The maximum compressive strength at 3 and 7days are 65.264MPa and 68.863MPa respectively corresponding to a POFA replacement of 40%. A replacement of 80% POFA to 20% Metakaolin gave compressive strength as high as 26.174MPa and 30.791MPa for 3 and 7 days. It was also discovered that water demand of the system reduced with increase in POFA replacement. It is concluded that POFA addition to metakaolin can improve behavior of Metakaolin and POFA geopolymer system.

Strength and Durability Characteristics of Polymer Modified Concrete Incorporating Vinyl Acetate Effluent

Waste generation from surface coating industries brings about worsening of the environmental scenery and human health in the world. The production of these wastes is detrimental to surrounding areas in landfill or dumping spaces, therefore necessary action is required to minimize the unpleasant situation. This research is aimed at using waste generated from the manufacture of paint known as vinyl acetate effluent as an admixture in concrete. The material is rinse water taken from the cleaning process reactor. Concrete of 0% vinyl acetate effluent cured in water with those of 2.5%, 5%, 10% and 20% by weight of cement were produced and cured using Japanese standard. The specimens were tested for compressive strength, splitting tensile strength and durability at 3, 7 and 28 days. Findings show that incorporating of 2.5% of Vinyl acetate effluent improves strength properties of concrete. Higher resistance of water absorption and sulfate conditions were observed in polymer modified concrete. The study has shown that incorporating vinyl acetate effluent in producing polymer modified concrete could bring lights of using the waste material for sustainable and environmental preservations.